1. Field of the Invention
The present invention generally relates to shoes, and, more particularly, to pneumatic cushioning therein.
2. Discussion of the Background
Prior art shoes have involved a variety of inflation devices disposed at different locations. For instance, previous shoe arrangements have included soles that can be inflated at the arch to provide support. Other shoes contain soles which have sealed inflated chambers disposed within the soles in order to increase vertical bounce. These previous chambers are soft-sided bladders which distort into a more convex or spherical shape upon inflation. If the walls of the bladder are not constrained, for instance, by the structure of the sole of the shoe, the distortion occurs in every direction.
Others have addressed this problem by placing a foam core inside the bladder and adhering the entire surface of the interior bladder walls to the entire exterior surface of the foam core as is taught in U.S. Pat. No. 5,235,715 to Donzis. This arrangement of adhering all of the surface of the foam core limits the shape of the bladder to the shape of the foam core and does not allow for differential distortions of the bladder as the bladder is inflated. Such prior art shoes also have not allowed for selective adjustment of the pressure in the bladder chambers and may result in uneven air distribution in the sole of the shoe.
Pumps in prior art shoes have typically been either externally connectable to the shoe's air chambers or positioned in low stress areas on the upper portion of the shoe such as in the tongue or on the back of the heel. Such prior art shoes encounter different problems in use. For externally connectable pumps, the pump must be retrieved whenever inflation is desired. Pumps positioned on the upper portion add bulk to the shoe and limit agility. Such pumps also inhibit aesthetic choices in shoe design. Aesthetics may be particularly vital for golf shoes or non-athletic shoes.
In addition, the typical prior art shoe arrangements have either utilized pump actuators which were nonintegral with the shoe and required connection before inflation and disconnection before normal shoe use, or pump actuators which were connected to the external surface of the shoe, such as on the heel as in U.S. Pat. No. 5,222,312 to Doyle. Nonintegral pump actuators require that the shoe wearer retrieve the actuator every time inflation is needed. External pump actuators impose aesthetic limitations on footwear and add bulk to the “footprint” of the footwear.
Prior art shoes which have incorporated adjustable pneumatic cushioning have typically provided several air chambers in different areas of the sole which are interconnected via tubing. Eliminating the use of several distinct chambers would further reduce the weight of the shoe and simplify shoe construction. In addition, a complementary configuration between the pump, pump actuator, air release valve, and the air chamber or bladder could significantly reduce the bulk of the shoe.
It is, therefore, desirable to provide for improved pneumatic cushioning in footwear while including all necessary components for such cushioning within shoe and minimizing shoe bulk and aesthetic limitations. A shoe sole which addresses the problems of known footwear would be an important advance in the art.